Now I understand better some of what's going on. The networking functions are fine; it's the GUI that's misleading me.
As soon as I select a server icon in the "Shared" section of the Finder sidebar, Leopard connects as "Guest" and displays the share points. Select a share point and the shared volume icon mounts on the desktop, and the triangular unmount icon appears next to the share icon in the Finder.
BUT: disconnect from server or share point, and the Finder STILL displays all share points and indicates I am still "Connected as: Guest" . . . but now there is no disconnect triangle.
Further weirdness: If I have a share point mounted, and click "Connect as" (button available in column-view), it unmounts the share, but doesn't launch the "Connect to Server" dialog.
Then, click "Connect as" again to bring up the "Connect to Server" dialog, authenticate as NON-GUEST user to an SMB share, the volume mounts, but the Finder displays "Connected as Guest"!
Even if I connect as a NON-GUEST user to a PC share using SMB in the older way -- CMD-K or "Go > Connect to Server" -- then select the newly-mounted Server icon in the Finder sidebar, the Finder tells me I am -- you "guest" it -- "Connected as Guest."
Interestingly, the Finder displays AFP connections correctly, with actual user names, and a "disconnect" button, under the server icon in the 1st Finder column; SMB connections do not.
So my issues here seem to be confusion created by miscues in the GUI -- the "Connected as Guest" indication before you've actually connected, and after you've disconnected. And for SMB connections, the additional miscues of being told you're connected as guest instead of the user account you've authenticated under, and the curious absence of a "Disconnect" button under the server icon in the 1st Finder column.
I just installed Leopard three days ago. Overall, I love it. I hope this feedback helps Apple refine some minor bumps in the user experience.
Message was edited by: Samildanach